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Langmuir–Blodgett Films of Hexamolybdate and Naphthylamine Prepared by Two Different Approaches: Synthesis, Characterization, and Materials Properties
Author(s) -
Liu Qian,
Hu Lei,
Fu Hui,
Yang Jun,
Fu QiaoMin,
Liu Li,
Liu ShiZhong,
Du ZuLiang,
Ho CheukLam,
Dai FengRong,
Wong WaiYeung
Publication year - 2012
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201100972
Subject(s) - langmuir–blodgett film , chemistry , acetonitrile , supramolecular chemistry , crystallography , luminescence , monolayer , anhydrous , fluorescence , aqueous solution , analytical chemistry (journal) , organic chemistry , crystal structure , materials science , physics , biochemistry , optoelectronics , quantum mechanics
Two novel covalently‐linked organic‐inorganic hybrid compounds [( n ‐C 4 H 9 ) 4 N] 2 [Mo 6 O 18 {≡N–(2‐Np)}] (NA–Mo6) and [( n ‐C 4 H 9 ) 4 N] 2 [Mo 6 O 17 {≡N–(1‐Np)} 2 ] (NA2–Mo6) (2‐Np = 2‐naphthyl; 1‐Np = 1‐naphthyl) have been prepared by the reaction of 2‐naphthylamine (2‐NpNH 2 ) or 1‐naphthylamine (1‐NpNH 2 ) with [( n ‐C 4 H 9 ) 4 N] 2 [Mo 6 O 19 ] (Mo6) in the presence of N , N′ ‐dicyclohexylcarbodiimide (DCC) in anhydrous acetonitrile, and have been characterized by 1 H NMR, IR, UV/Vis, and fluorescence spectra as well as X‐ray crystallography. Structural analyses reveal the formation of self‐assembled infinite 1‐D and 3‐D supramolecular frameworks. The UV/Vis spectra of NA–Mo6 and NA2–Mo6 show that the lowest energy electronic transfers occur at 362 and 394 nm, respectively, which are dramatically red‐shifted when compared to that of Mo6. The luminescence studies show that Mo6 can notably quench the emission of naphthylamine. Monolayer and multilayer films of NA–Mo6 and NA2–Mo6 were fabricated on different substrates by the Langmuir–Blodgett (LB) technique using H 2 O as the subphase. For comparison, another two types of organic‐inorganic hybrid films composed of noncovalently‐linked 1‐NpNH 2 /Mo6 and 2‐NpNH 2 /Mo6 systems were also deposited onto the same substrates under the same conditions by the LB technique using an aqueous solution of Mo6 as the subphase. The as‐prepared organic‐inorganic hybrid films were characterized by π‐A isotherms, UV/Vis absorption spectra, photoluminescence spectra, and scanning tunneling microscopy. The results indicate that stable monolayers can be formed at the air–water interface for NA–Mo6 and NA2–Mo6, and at the air–Mo6 solution interface for 1‐NpNH 2 and 2‐NpNH 2 . The four LB films containing NA–Mo6, NA2–Mo6, 1‐NpNH 2 /Mo6, and 2‐NpNH 2 /Mo6 display interesting electrical conductivity.